Megestrol acetate therapy and secondary adrenal suppression

BACKGROUND. Adrenal suppression has been noted in patients who are receivin g medroxyprogesterone acetate (MPA). Megestrol acetate (MA) is used to trea t patients with advanced breast carcinoma, cachaexia related to acquired im mune deficiency syndrome, and disseminated carcinomatosis, and it is believ ed to have fewer side effects than MPA. The aim of this study was to test f or secondary adrenal suppression in patients receiving MA therapy for advan ced metastatic cancer. METHODS. Ten postmenopausal female patients receiving long term MA therapy, nine with advanced metastatic breast carcinoma and one with metastatic ova rian carcinoma, were recruited consecutively from the oncology outpatient c linic at Ninewells Hospital in Dundee, Scotland. A short synacthen test and a corticotrophin-releasing hormone (CRH) stimulation test were performed o n two separate occasions. Urine collection for 24-hour urinary free cortiso l was performed on 6 patients. Follicle-stimulating hormone (FSH), lutenizi ng hormone (LH), thyroid-stimulating hormone (TSH), and free thyroxine (T4) were measured in eight patients. An insulin stress test (IST) was performe d on two patients. RESULTS. Nine of 10 patients had a poor cortisol response to the short syna cthen test. The CRH test had abnormal results in eight of nine patients. In all patients tested, 24-hour urinary free cortisol excretion was low, indi cating adrenal suppression. Basal serum FSH, LH, TSH, and free T4 values in dicated normal pituitary function. Adrenocorticotrophic hormone response in the CRH test varied and is discussed in this article. CONCLUSIONS. MA causes secondary adrenal suppression that is thought to be due to its effect at the hypothalamic level. The authors recommend a short course of steroid replacement for patients receiving MA at times of acute i llness. Cancer (C) 1999 American Cancer Society.